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Search: id:A141777
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| A141777 |
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Primes of the form -3*x^2+4*x*y+6*y^2 (as well as of the form 7*x^2+12*x*y+2*y^2). |
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3
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| 2, 7, 13, 29, 61, 79, 101, 109, 127, 149, 151, 167, 173, 197, 239, 263, 271, 277, 293, 349, 359, 373, 431, 439, 461, 479, 503, 541, 557, 607, 613, 677, 701, 733, 743, 821, 853, 877, 887, 919, 941, 967, 997
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OFFSET
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1,1
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COMMENT
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Discriminant = 88. Class = 2. Binary quadratic forms a*x^2+b*x*y+c*y^2 have discriminant d=b^2-4ac, and gcd(a,b,c)=1
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REFERENCES
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Borevich and Shafaewich, Number Theory.
D. B. Zagier, Zetafunktionen und quadratische Koerper
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EXAMPLE
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a(2)=7 because we can write 7= -3*1^2+4*1*1+6*1^2 (or 7=7*1^2+12*1*0+2*0^2
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CROSSREFS
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Cf. A141776 (d=88).
Sequence in context: A010895 A045376 A045377 this_sequence A127396 A079119 A051748
Adjacent sequences: A141774 A141775 A141776 this_sequence A141778 A141779 A141780
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KEYWORD
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nonn
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AUTHOR
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Laura Caballero Fernandez, Lourdes Calvo Moguer, Maria Josefa Cano Marquez, Oscar Jesus Falcon Ganfornina and Sergio Garrido Morales (sergarmor(AT)yahoo.es), Jul 04 2008
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